An agricultural seeding machine such as a row crop planter or grain drill places the seeds at a desired depth within a plurality of parallel seed trenches formed in the soil. In the case of a row crop planter, a plurality of row crop units are typically ground driven using wheels, shafts, sprockets, transfer cases, chains and the like. Each row crop unit has a frame which is movably coupled with a tool bar. The frame may carry a seed hopper, herbicide hopper and/or insecticide hopper. The mechanisms necessary to properly meter the seeds, dispense the seeds at a predetermined rate and place the seeds at predetermined relative locations within a seed trench are relatively complicated.
The mechanisms associated with metering and placing the seeds generally can be divided into a seed metering system and a seed placement system which are in communication with each other. The seed metering system, simply called a seed meter herein, receives the seeds in a bulk manner from a seed hopper. Different types of seed meters may be used such as seed plates, finger plates, and seed discs. Regardless of which type seed meter is used, the seeds are singulated and discharged at a predetermined rate to the seed placement system.
It is known to drive a seed meter with a variable rate drive using hydraulic motors and values. The use of such hydraulic systems for variably driving a seed meter drives all row units at the same population. Such systems may be relatively expensive, complicated and lack control on an individual row unit basis.
It is also known to provide an electric motor at each row unit for the purpose of driving the seed meter. Driving each seed meter with a corresponding electric motor requires a relatively large electric motor which consumes an excessive amount of electric power which is not typically available for current traction units (e.g., tractor) used for pulling the seeding machine. Using an all-electrical drive of this type therefore is not practical with existing traction units.
What is needed in the art is a drive for a seed meter which may be individually controlled but still derives the primary input power from the ground driven components of the seeding machine.